It takes close to 300 degrees C to boil oil whereas water boils at 100 degrees C.
Stihl 038 magnum
- Thread starter Burchie70
- Start date
Help Support Arborist Forum:
My first thought if it happened right after you bought it was, did he mistakenly have some gas in the oil tank? Maybe that was boiling and causing the heat?
Burchie70
ArboristSite Operative
I can’t be sure what he had in it but I have dumped out the oil tank since then. After I ran it the first time there was maybe a little less than 1/4 left. Anything is possible I guess
I don't think Bob was calling you a liar.
Just no evidence on out side of tank.
Just no evidence on out side of tank.
- Joined
- Jul 19, 2019
- Messages
- 4,627
- Reaction score
- 9,380
I wasnt indeed, but some folk get defensive real quick.
I mean Jerry has been around saws and such a bit longer than I and he has pointed out oil boils at 300 degrees- Stihl case paint yellows and scorches at a lesser temp than that.
So, yeah you picked it- I was merely pointing out there does not seem to be the evidence to support the claim and it is why I asked for video of the boiling oil so we could try to determine what the owner is seeing.
No signs of an overheat from the outside. Nice clean saw overall. Most saws of that age would have browning around the muffler. Nothing shows that.
So what happened? Hot oil on a cold day perhaps? You may be releasing trapped pressure. Remember, there is no pressure relief on a modern saw oil system, only an inlet check valve.
Is it running hot? Possibly. Cannot know that from here.
38s don't necessarily like to run lean or dull. They sound GREAT at 15000 rpm, but that is not where the power is. Or the lubrication.
So what happened? Hot oil on a cold day perhaps? You may be releasing trapped pressure. Remember, there is no pressure relief on a modern saw oil system, only an inlet check valve.
Is it running hot? Possibly. Cannot know that from here.
38s don't necessarily like to run lean or dull. They sound GREAT at 15000 rpm, but that is not where the power is. Or the lubrication.
+1 for maybe lean. But, hot enough to boil oil, but no piston damage...a very fine line, I assume.
My morning AWG. Hot gasses leaking into the oil tank. Start saw, get up to temp, flip saw onto its side, check for positive pressure in the oil tank.
I still think IR thermometer readings might prove helpful.
Highly interesting case.
Roy
My morning AWG. Hot gasses leaking into the oil tank. Start saw, get up to temp, flip saw onto its side, check for positive pressure in the oil tank.
I still think IR thermometer readings might prove helpful.
Highly interesting case.
Roy
Vacuum and pressure test. Slightly loosen the oil cap and spray soapy water around it. Should not make bubbles.
In the case of a case gasket leaking into the tank, there should be blue smoke. The piston is making vacuum and pressure in the case. But, strange things do happen.
In the case of a case gasket leaking into the tank, there should be blue smoke. The piston is making vacuum and pressure in the case. But, strange things do happen.
I'll go with someone put some mix in the oil tank by mistake.
So dump that oil out and try another type and see what happens.
Burchie70
ArboristSite Operative
I finally had a chance to look at the saw. I don’t believe anything I found would make the oil boil but maybe Mad Professor is right and the guy who I got it from put mix in the oil tank by mistake. I also think I’m mistaken and I never did a carb kit on this saw, I may of been thinking of my 044. But this is what I did. I pulled the carb apart and put a new kit in it. I found that the strainer screen in the carb was plugged with rusty looking material. Also I pulled the muffler off and found a piece of the exhaust gasket was gone so I put a new one on it. I dumped the oil out and flushed the tank out, filled everything up and ran it for a few minutes and it seems fine but I’ll run it longer when I get time. Oh I also changed the oil tank vent
What RPM is it tuned at?
Does it Four-stroke easily?
Burchie70
ArboristSite Operative
I haven’t checked the rpm’s yet or adjusted the carb yet. After doing the carb kit I have the high and low speed jets set at 1 turn out. It doesn’t seem to be over revving
Just a thought ,but the case gasket could be broken between the bottom of the cylinder and the oil tank. That would certainly create bubbles and excessive heat. Usually oil will seep into the crank case but not always.
You'll have to do a pressure test to confirm.
You'll have to do a pressure test to confirm.
